/*      $NetBSD: zynq_uart.c,v 1.6 2024/05/04 02:04:54 dyoung Exp $     */

/*
 * Copyright (c) 2012  Genetec Corporation.  All rights reserved.
 * Written by Hiroyuki Bessho, Hashimoto Kenichi for Genetec Corporation.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY GENETEC CORPORATION ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
 * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL GENETEC CORPORATION
 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
 * POSSIBILITY OF SUCH DAMAGE.
 *
 */

/*
 * derived from sys/dev/ic/com.c
 */

/*-
 * Copyright (c) 1998, 1999, 2004, 2008 The NetBSD Foundation, Inc.
 * All rights reserved.
 *
 * This code is derived from software contributed to The NetBSD Foundation
 * by Charles M. Hannum.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
 * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
 * POSSIBILITY OF SUCH DAMAGE.
 */

/*
 * Copyright (c) 1991 The Regents of the University of California.
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. Neither the name of the University nor the names of its contributors
 *    may be used to endorse or promote products derived from this software
 *    without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 *
 *      @(#)com.c       7.5 (Berkeley) 5/16/91
 */

/*
 * driver for UART in Zynq-7000.
 */

#include <sys/cdefs.h>
__KERNEL_RCSID(0, "$NetBSD: zynq_uart.c,v 1.6 2024/05/04 02:04:54 dyoung Exp $");

#include "opt_soc.h"
#include "opt_console.h"
#include "opt_com.h"
#include "opt_ddb.h"
#include "opt_kgdb.h"
#include "opt_ntp.h"

/*
 * Override cnmagic(9) macro before including <sys/systm.h>.
 * We need to know if cn_check_magic triggered debugger, so set a flag.
 * Callers of cn_check_magic must declare int cn_trapped = 0;
 * XXX: this is *ugly*!
 */
#define cn_trap()                               \
        do {                                    \
                console_debugger();             \
                cn_trapped = 1;                 \
        } while (/* CONSTCOND */ 0)

#include <sys/param.h>

#include <sys/bus.h>
#include <sys/conf.h>
#include <dev/cons.h>
#include <sys/device.h>
#include <sys/file.h>
#include <sys/kauth.h>
#include <sys/kernel.h>
#include <sys/kmem.h>
#include <sys/poll.h>
#include <sys/proc.h>
#include <sys/systm.h>
#include <sys/tty.h>

#include <ddb/db_active.h>

#ifdef RND_COM
#include <sys/rndsource.h>
#endif

#include <arm/xilinx/zynq_uartreg.h>
#include <arm/xilinx/zynq_uartvar.h>

#ifndef ZYNQUART_RING_SIZE
#define ZYNQUART_RING_SIZE      2048
#endif

#define UART_SIZE               0x00000048

typedef struct zynquart_softc {
        device_t        sc_dev;

        struct zynquart_regs {
                bus_space_tag_t         ur_iot;
                bus_space_handle_t      ur_ioh;
                bus_addr_t              ur_iobase;
        } sc_regs;

#define sc_bt   sc_regs.ur_iot
#define sc_bh   sc_regs.ur_ioh

        uint32_t        sc_intrspec_enb;
        uint32_t        sc_cr;
        uint32_t        sc_mcr;
        uint32_t        sc_msr;

        uint            sc_init_cnt;

        bus_addr_t      sc_addr;
        bus_size_t      sc_size;

        u_char  sc_hwflags;
/* Hardware flag masks */
#define ZYNQUART_HW_FLOW        __BIT(0)
#define ZYNQUART_HW_DEV_OK      __BIT(1)
#define ZYNQUART_HW_CONSOLE     __BIT(2)
#define ZYNQUART_HW_KGDB        __BIT(3)

        bool    enabled;

        u_char  sc_swflags;

        u_char sc_rx_flags;
#define ZYNQUART_RX_TTY_BLOCKED         __BIT(0)
#define ZYNQUART_RX_TTY_OVERFLOWED      __BIT(1)
#define ZYNQUART_RX_IBUF_BLOCKED        __BIT(2)
#define ZYNQUART_RX_IBUF_OVERFLOWED     __BIT(3)
#define ZYNQUART_RX_ANY_BLOCK                                   \
        (ZYNQUART_RX_TTY_BLOCKED|ZYNQUART_RX_TTY_OVERFLOWED|    \
            ZYNQUART_RX_IBUF_BLOCKED|ZYNQUART_RX_IBUF_OVERFLOWED)

        bool    sc_tx_busy, sc_tx_done, sc_tx_stopped;
        bool    sc_rx_ready,sc_st_check;
        u_short sc_txfifo_len, sc_txfifo_thresh;

        uint16_t        *sc_rbuf;
        u_int           sc_rbuf_size;
        u_int           sc_rbuf_in;
        u_int           sc_rbuf_out;
#define ZYNQUART_RBUF_AVAIL(sc)                                 \
        ((sc->sc_rbuf_out <= sc->sc_rbuf_in) ?                  \
        (sc->sc_rbuf_in - sc->sc_rbuf_out) :                    \
        (sc->sc_rbuf_size - (sc->sc_rbuf_out - sc->sc_rbuf_in)))

#define ZYNQUART_RBUF_SPACE(sc) \
        ((sc->sc_rbuf_in <= sc->sc_rbuf_out ?                       \
            sc->sc_rbuf_size - (sc->sc_rbuf_out - sc->sc_rbuf_in) : \
            sc->sc_rbuf_in - sc->sc_rbuf_out) - 1)
/* increment ringbuffer pointer */
#define ZYNQUART_RBUF_INC(sc,v,i)       (((v) + (i))&((sc->sc_rbuf_size)-1))
        u_int   sc_r_lowat;
        u_int   sc_r_hiwat;

        /* output chunk */
        u_char *sc_tba;
        u_int sc_tbc;
        u_int sc_heldtbc;
        /* pending parameter changes */
        u_char  sc_pending;
#define ZYNQUART_PEND_PARAM     __BIT(0)
#define ZYNQUART_PEND_SPEED     __BIT(1)


        struct callout sc_diag_callout;
        kmutex_t sc_lock;
        void *sc_ih;            /* interrupt handler */
        void *sc_si;            /* soft interrupt */
        struct tty              *sc_tty;

        /* power management hooks */
        int (*enable)(struct zynquart_softc *);
        void (*disable)(struct zynquart_softc *);

        struct {
                ulong err;
                ulong brk;
                ulong prerr;
                ulong frmerr;
                ulong ovrrun;
        }       sc_errors;

        struct zynquart_baudrate_ratio {
                uint16_t numerator;     /* UBIR */
                uint16_t modulator;     /* UBMR */
        } sc_ratio;

} zynquart_softc_t;


int     zynquartspeed(long, struct zynquart_baudrate_ratio *);
int     zynquartparam(struct tty *, struct termios *);
void    zynquartstart(struct tty *);
int     zynquarthwiflow(struct tty *, int);

void    zynquart_shutdown(struct zynquart_softc *);
void    zynquart_loadchannelregs(struct zynquart_softc *);
void    zynquart_hwiflow(struct zynquart_softc *);
void    zynquart_break(struct zynquart_softc *, bool);
void    zynquart_modem(struct zynquart_softc *, int);
void    tiocm_to_zynquart(struct zynquart_softc *, u_long, int);
int     zynquart_to_tiocm(struct zynquart_softc *);
void    zynquart_iflush(struct zynquart_softc *);

int     zynquart_common_getc(dev_t, struct zynquart_regs *);
void    zynquart_common_putc(dev_t, struct zynquart_regs *, int);


int     zynquart_init(struct zynquart_regs *, int, tcflag_t);

int     zynquartcngetc(dev_t);
void    zynquartcnputc(dev_t, int);

static void zynquartintr_read(struct zynquart_softc *);
static void zynquartintr_send(struct zynquart_softc *);

static void zynquart_enable_debugport(struct zynquart_softc *);
static void zynquart_disable_all_interrupts(struct zynquart_softc *);
static void zynquart_control_rxint(struct zynquart_softc *, bool);
static void zynquart_control_txint(struct zynquart_softc *, bool);

static  uint32_t cflag_to_zynquart(tcflag_t, uint32_t);

#define integrate       static inline
void    zynquartsoft(void *);
integrate void zynquart_rxsoft(struct zynquart_softc *, struct tty *);
integrate void zynquart_txsoft(struct zynquart_softc *, struct tty *);
integrate void zynquart_stsoft(struct zynquart_softc *, struct tty *);
integrate void zynquart_schedrx(struct zynquart_softc *);
void    zynquartdiag(void *);
static void zynquart_load_speed(struct zynquart_softc *);
static void zynquart_load_params(struct zynquart_softc *);
integrate void zynquart_load_pendings(struct zynquart_softc *);


extern struct cfdriver zynquart_cd;

dev_type_open(zynquartopen);
dev_type_close(zynquartclose);
dev_type_read(zynquartread);
dev_type_write(zynquartwrite);
dev_type_ioctl(zynquartioctl);
dev_type_stop(zynquartstop);
dev_type_tty(zynquarttty);
dev_type_poll(zynquartpoll);

const struct cdevsw zynquart_cdevsw = {
        .d_open = zynquartopen,
        .d_close = zynquartclose,
        .d_read = zynquartread,
        .d_write = zynquartwrite,
        .d_ioctl = zynquartioctl,
        .d_stop = zynquartstop,
        .d_tty = zynquarttty,
        .d_poll = zynquartpoll,
        .d_mmap = nommap,
        .d_kqfilter = ttykqfilter,
        .d_discard = nodiscard,
        .d_flag = D_TTY
};

/*
 * Make this an option variable one can patch.
 * But be warned:  this must be a power of 2!
 */
u_int zynquart_rbuf_size = ZYNQUART_RING_SIZE;

/* Stop input when 3/4 of the ring is full; restart when only 1/4 is full. */
u_int zynquart_rbuf_hiwat = (ZYNQUART_RING_SIZE * 1) / 4;
u_int zynquart_rbuf_lowat = (ZYNQUART_RING_SIZE * 3) / 4;

static struct zynquart_regs zynquartconsregs;
static int zynquartconsattached;
static int zynquartconsrate;
static tcflag_t zynquartconscflag;
static struct cnm_state zynquart_cnm_state;

u_int zynquart_freq;
u_int zynquart_freqdiv;

#ifdef KGDB
#include <sys/kgdb.h>

static struct zynquart_regs zynquart_kgdb_regs;
static int zynquart_kgdb_attached;

int     zynquart_kgdb_getc(void *);
void    zynquart_kgdb_putc(void *, int);
#endif /* KGDB */

#define ZYNQUART_UNIT_MASK      0x7ffff
#define ZYNQUART_DIALOUT_MASK   0x80000

#define ZYNQUART_UNIT(x)        (minor(x) & ZYNQUART_UNIT_MASK)
#define ZYNQUART_DIALOUT(x)     (minor(x) & ZYNQUART_DIALOUT_MASK)

#define ZYNQUART_ISALIVE(sc)    ((sc)->enabled != 0 && \
                         device_is_active((sc)->sc_dev))

#define BR      BUS_SPACE_BARRIER_READ
#define BW      BUS_SPACE_BARRIER_WRITE
#define ZYNQUART_BARRIER(r, f) \
        bus_space_barrier((r)->ur_iot, (r)->ur_ioh, 0, UART_SIZE, (f))

CFATTACH_DECL_NEW(zynquart, sizeof(struct zynquart_softc),
    zynquart_match, zynquart_attach, NULL, NULL);

void
zynquart_attach_common(device_t parent, device_t self,
    bus_space_tag_t iot, paddr_t iobase, size_t size, int flags)
{
        zynquart_softc_t *sc = device_private(self);
        struct zynquart_regs *regsp = &sc->sc_regs;
        struct tty *tp;
        bus_space_handle_t ioh;

        aprint_naive("\n");
        aprint_normal("\n");

        sc->sc_dev = self;

        if (size <= 0)
                size = UART_SIZE;

        regsp->ur_iot = iot;
        regsp->ur_iobase = iobase;

        if (bus_space_map(iot, regsp->ur_iobase, size, 0, &ioh)) {
                return;
        }
        regsp->ur_ioh = ioh;

        callout_init(&sc->sc_diag_callout, 0);
        mutex_init(&sc->sc_lock, MUTEX_DEFAULT, IPL_HIGH);

        sc->sc_cr = bus_space_read_4(iot, ioh, UART_CONTROL);
        sc->sc_cr |= CR_TXEN | CR_RXEN;
        sc->sc_cr &= ~(CR_TXDIS | CR_RXDIS);
        bus_space_write_4(iot, ioh, UART_CONTROL, sc->sc_cr);

        /* Disable interrupts before configuring the device. */
        zynquart_disable_all_interrupts(sc);

        if (regsp->ur_iobase == zynquartconsregs.ur_iobase) {
                zynquartconsattached = 1;

                /* Make sure the console is always "hardwired". */
                SET(sc->sc_hwflags, ZYNQUART_HW_CONSOLE);
                SET(sc->sc_swflags, TIOCFLAG_SOFTCAR);
        }

        tp = tty_alloc();
        tp->t_oproc = zynquartstart;
        tp->t_param = zynquartparam;
        tp->t_hwiflow = zynquarthwiflow;

        sc->sc_tty = tp;
        sc->sc_rbuf = kmem_alloc(sizeof (*sc->sc_rbuf) * zynquart_rbuf_size,
            KM_SLEEP);
        sc->sc_rbuf_size = zynquart_rbuf_size;
        sc->sc_rbuf_in = sc->sc_rbuf_out = 0;
        sc->sc_txfifo_len = 64;
        sc->sc_txfifo_thresh = 32;

        tty_attach(tp);

        if (ISSET(sc->sc_hwflags, ZYNQUART_HW_CONSOLE)) {
                int maj;

                /* locate the major number */
                maj = cdevsw_lookup_major(&zynquart_cdevsw);

                if (maj != NODEVMAJOR) {
                        tp->t_dev = cn_tab->cn_dev = makedev(maj,
                            device_unit(sc->sc_dev));

                        aprint_normal_dev(sc->sc_dev, "console\n");
                }
        }

        /* reset receive time out */
        bus_space_write_4(iot, ioh, UART_RCVR_TIMEOUT, 0);
        bus_space_write_4(iot, ioh, UART_RCVR_FIFO_TRIGGER, 1);

#ifdef KGDB
        /*
         * Allow kgdb to "take over" this port.  If this is
         * not the console and is the kgdb device, it has
         * exclusive use.  If it's the console _and_ the
         * kgdb device, it doesn't.
         */
        if (regsp->ur_iobase == zynquart_kgdb_regs.ur_iobase) {
                if (!ISSET(sc->sc_hwflags, ZYNQUART_HW_CONSOLE)) {
                        zynquart_kgdb_attached = 1;

                        SET(sc->sc_hwflags, ZYNQUART_HW_KGDB);
                }
                aprint_normal_dev(sc->sc_dev, "kgdb\n");
        }
#endif

        sc->sc_si = softint_establish(SOFTINT_SERIAL, zynquartsoft, sc);

#ifdef RND_COM
        rnd_attach_source(&sc->rnd_source, device_xname(sc->sc_dev),
                          RND_TYPE_TTY, 0);
#endif

        /* if there are no enable/disable functions, assume the device
           is always enabled */
        if (!sc->enable)
                sc->enabled = 1;

        zynquart_enable_debugport(sc);

        SET(sc->sc_hwflags, ZYNQUART_HW_DEV_OK);
}

int
zynquartspeed(long speed, struct zynquart_baudrate_ratio *ratio)
{
        return 0;
}

#ifdef ZYNQUART_DEBUG
int     zynquart_debug = 0;

void zynquartstatus(struct zynquart_softc *, const char *);
void
zynquartstatus(struct zynquart_softc *sc, const char *str)
{
        struct tty *tp = sc->sc_tty;

        aprint_normal_dev(sc->sc_dev,
            "%s %cclocal  %cdcd %cts_carr_on %cdtr %ctx_stopped\n",
            str,
            ISSET(tp->t_cflag, CLOCAL) ? '+' : '-',
            ISSET(sc->sc_msr, MSR_DCD) ? '+' : '-',
            ISSET(tp->t_state, TS_CARR_ON) ? '+' : '-',
            ISSET(sc->sc_mcr, MCR_DTR) ? '+' : '-',
            sc->sc_tx_stopped ? '+' : '-');

        aprint_normal_dev(sc->sc_dev,
            "%s %ccrtscts %ccts %cts_ttstop  %crts rx_flags=0x%x\n",
            str,
            ISSET(tp->t_cflag, CRTSCTS) ? '+' : '-',
            ISSET(sc->sc_msr, MSR_CTS) ? '+' : '-',
            ISSET(tp->t_state, TS_TTSTOP) ? '+' : '-',
            ISSET(sc->sc_mcr, MCR_RTS) ? '+' : '-',
            sc->sc_rx_flags);
}
#endif

#if 0
int
zynquart_detach(device_t self, int flags)
{
        struct zynquart_softc *sc = device_private(self);
        int maj, mn;

        if (ISSET(sc->sc_hwflags, ZYNQUART_HW_CONSOLE))
                return EBUSY;

        /* locate the major number */
        maj = cdevsw_lookup_major(&zynquart_cdevsw);

        /* Nuke the vnodes for any open instances. */
        mn = device_unit(self);
        vdevgone(maj, mn, mn, VCHR);

        mn |= ZYNQUART_DIALOUT_MASK;
        vdevgone(maj, mn, mn, VCHR);

        if (sc->sc_rbuf == NULL) {
                /*
                 * Ring buffer allocation failed in the zynquart_attach_subr,
                 * only the tty is allocated, and nothing else.
                 */
                tty_free(sc->sc_tty);
                return 0;
        }

        /* Free the receive buffer. */
        kmem_free(sc->sc_rbuf, sizeof(*sc->sc_rbuf) * sc->sc_rbuf_size);

        /* Detach and free the tty. */
        tty_detach(sc->sc_tty);
        tty_free(sc->sc_tty);

        /* Unhook the soft interrupt handler. */
        softint_disestablish(sc->sc_si);

#ifdef RND_COM
        /* Unhook the entropy source. */
        rnd_detach_source(&sc->rnd_source);
#endif
        callout_destroy(&sc->sc_diag_callout);

        /* Destroy the lock. */
        mutex_destroy(&sc->sc_lock);

        return (0);
}
#endif

#ifdef notyet
int
zynquart_activate(device_t self, enum devact act)
{
        struct zynquart_softc *sc = device_private(self);
        int rv = 0;

        switch (act) {
        case DVACT_ACTIVATE:
                rv = EOPNOTSUPP;
                break;

        case DVACT_DEACTIVATE:
                if (sc->sc_hwflags & (ZYNQUART_HW_CONSOLE|ZYNQUART_HW_KGDB)) {
                        rv = EBUSY;
                        break;
                }

                if (sc->disable != NULL && sc->enabled != 0) {
                        (*sc->disable)(sc);
                        sc->enabled = 0;
                }
                break;
        }

        return (rv);
}
#endif

void
zynquart_shutdown(struct zynquart_softc *sc)
{
        struct tty *tp = sc->sc_tty;

        mutex_spin_enter(&sc->sc_lock);

        /* If we were asserting flow control, then deassert it. */
        SET(sc->sc_rx_flags, ZYNQUART_RX_IBUF_BLOCKED);
        zynquart_hwiflow(sc);

        /* Clear any break condition set with TIOCSBRK. */
        zynquart_break(sc, false);

        /*
         * Hang up if necessary.  Wait a bit, so the other side has time to
         * notice even if we immediately open the port again.
         * Avoid tsleeping above splhigh().
         */
        if (ISSET(tp->t_cflag, HUPCL)) {
                zynquart_modem(sc, 0);
                mutex_spin_exit(&sc->sc_lock);
                /* XXX will only timeout */
                (void) kpause(ttclos, false, hz, NULL);
                mutex_spin_enter(&sc->sc_lock);
        }

        /* Turn off interrupts. */
        zynquart_disable_all_interrupts(sc);
        /* re-enable recv interrupt for console or kgdb port */
        zynquart_enable_debugport(sc);

        mutex_spin_exit(&sc->sc_lock);

#ifdef  notyet
        if (sc->disable) {
#ifdef DIAGNOSTIC
                if (!sc->enabled)
                        panic("zynquart_shutdown: not enabled?");
#endif
                (*sc->disable)(sc);
                sc->enabled = 0;
        }
#endif
}

int
zynquartopen(dev_t dev, int flag, int mode, struct lwp *l)
{
        struct zynquart_softc *sc;
        struct tty *tp;
        int s;
        int error;

        sc = device_lookup_private(&zynquart_cd, ZYNQUART_UNIT(dev));
        if (sc == NULL || !ISSET(sc->sc_hwflags, ZYNQUART_HW_DEV_OK) ||
                sc->sc_rbuf == NULL)
                return (ENXIO);

        if (!device_is_active(sc->sc_dev))
                return (ENXIO);

#ifdef KGDB
        /*
         * If this is the kgdb port, no other use is permitted.
         */
        if (ISSET(sc->sc_hwflags, ZYNQUART_HW_KGDB))
                return (EBUSY);
#endif

        tp = sc->sc_tty;

        if (kauth_authorize_device_tty(l->l_cred, KAUTH_DEVICE_TTY_OPEN, tp))
                return (EBUSY);

        s = spltty();

        /*
         * Do the following iff this is a first open.
         */
        if (!ISSET(tp->t_state, TS_ISOPEN) && tp->t_wopen == 0) {
                struct termios t;

                tp->t_dev = dev;


#ifdef notyet
                if (sc->enable) {
                        if ((*sc->enable)(sc)) {
                                splx(s);
                                aprint_error_dev(sc->sc_dev,
                                    "device enable failed\n");
                                return (EIO);
                        }
                        sc->enabled = 1;
                }
#endif

                mutex_spin_enter(&sc->sc_lock);

                zynquart_disable_all_interrupts(sc);

                /* Fetch the current modem control status, needed later. */

#ifdef  ZYNQUART_PPS
                /* Clear PPS capture state on first open. */
                mutex_spin_enter(&timecounter_lock);
                memset(&sc->sc_pps_state, 0, sizeof(sc->sc_pps_state));
                sc->sc_pps_state.ppscap = PPS_CAPTUREASSERT | PPS_CAPTURECLEAR;
                pps_init(&sc->sc_pps_state);
                mutex_spin_exit(&timecounter_lock);
#endif

                mutex_spin_exit(&sc->sc_lock);

                /*
                 * Initialize the termios status to the defaults.  Add in the
                 * sticky bits from TIOCSFLAGS.
                 */
                if (ISSET(sc->sc_hwflags, ZYNQUART_HW_CONSOLE)) {
                        t.c_ospeed = zynquartconsrate;
                        t.c_cflag = zynquartconscflag;
                } else {
                        t.c_ospeed = TTYDEF_SPEED;
                        t.c_cflag = TTYDEF_CFLAG;
                }
                t.c_ispeed = t.c_ospeed;
                if (ISSET(sc->sc_swflags, TIOCFLAG_CLOCAL))
                        SET(t.c_cflag, CLOCAL);
                if (ISSET(sc->sc_swflags, TIOCFLAG_CRTSCTS))
                        SET(t.c_cflag, CRTSCTS);
                if (ISSET(sc->sc_swflags, TIOCFLAG_MDMBUF))
                        SET(t.c_cflag, MDMBUF);
                /* Make sure zynquartparam() will do something. */
                tp->t_ospeed = 0;
                (void) zynquartparam(tp, &t);
                tp->t_iflag = TTYDEF_IFLAG;
                tp->t_oflag = TTYDEF_OFLAG;
                tp->t_lflag = TTYDEF_LFLAG;
                ttychars(tp);
                ttsetwater(tp);

                mutex_spin_enter(&sc->sc_lock);

                /*
                 * Turn on DTR.  We must always do this, even if carrier is not
                 * present, because otherwise we'd have to use TIOCSDTR
                 * immediately after setting CLOCAL, which applications do not
                 * expect.  We always assert DTR while the device is open
                 * unless explicitly requested to deassert it.
                 */
                zynquart_modem(sc, 1);

                /* Clear the input ring, and unblock. */
                sc->sc_rbuf_in = sc->sc_rbuf_out = 0;
                zynquart_iflush(sc);
                CLR(sc->sc_rx_flags, ZYNQUART_RX_ANY_BLOCK);
                zynquart_hwiflow(sc);

                /* Turn on interrupts. */
                zynquart_control_rxint(sc, true);

#ifdef ZYNQUART_DEBUG
                if (zynquart_debug)
                        zynquartstatus(sc, "zynquartopen  ");
#endif

                mutex_spin_exit(&sc->sc_lock);
        }

        splx(s);

#if 0
        error = ttyopen(tp, ZYNQUART_DIALOUT(dev), ISSET(flag, O_NONBLOCK));
#else
        error = ttyopen(tp, 1, ISSET(flag, O_NONBLOCK));
#endif
        if (error)
                goto bad;

        error = (*tp->t_linesw->l_open)(dev, tp);
        if (error)
                goto bad;

        return (0);

bad:
        if (!ISSET(tp->t_state, TS_ISOPEN) && tp->t_wopen == 0) {
                /*
                 * We failed to open the device, and nobody else had it opened.
                 * Clean up the state as appropriate.
                 */
                zynquart_shutdown(sc);
        }

        return (error);
}

int
zynquartclose(dev_t dev, int flag, int mode, struct lwp *l)
{
        struct zynquart_softc *sc =
            device_lookup_private(&zynquart_cd, ZYNQUART_UNIT(dev));
        struct tty *tp = sc->sc_tty;

        /* XXX This is for cons.c. */
        if (!ISSET(tp->t_state, TS_ISOPEN))
                return (0);

        (*tp->t_linesw->l_close)(tp, flag);
        ttyclose(tp);

        if (ZYNQUART_ISALIVE(sc) == 0)
                return (0);

        if (!ISSET(tp->t_state, TS_ISOPEN) && tp->t_wopen == 0) {
                /*
                 * Although we got a last close, the device may still be in
                 * use; e.g. if this was the dialout node, and there are still
                 * processes waiting for carrier on the non-dialout node.
                 */
                zynquart_shutdown(sc);
        }

        return (0);
}

int
zynquartread(dev_t dev, struct uio *uio, int flag)
{
        struct zynquart_softc *sc =
            device_lookup_private(&zynquart_cd, ZYNQUART_UNIT(dev));
        struct tty *tp = sc->sc_tty;

        if (ZYNQUART_ISALIVE(sc) == 0)
                return (EIO);

        return ((*tp->t_linesw->l_read)(tp, uio, flag));
}

int
zynquartwrite(dev_t dev, struct uio *uio, int flag)
{
        struct zynquart_softc *sc =
            device_lookup_private(&zynquart_cd, ZYNQUART_UNIT(dev));
        struct tty *tp = sc->sc_tty;

        if (ZYNQUART_ISALIVE(sc) == 0)
                return (EIO);

        return ((*tp->t_linesw->l_write)(tp, uio, flag));
}

int
zynquartpoll(dev_t dev, int events, struct lwp *l)
{
        struct zynquart_softc *sc =
            device_lookup_private(&zynquart_cd, ZYNQUART_UNIT(dev));
        struct tty *tp = sc->sc_tty;

        if (ZYNQUART_ISALIVE(sc) == 0)
                return (POLLHUP);

        return ((*tp->t_linesw->l_poll)(tp, events, l));
}

struct tty *
zynquarttty(dev_t dev)
{
        struct zynquart_softc *sc =
            device_lookup_private(&zynquart_cd, ZYNQUART_UNIT(dev));
        struct tty *tp = sc->sc_tty;

        return (tp);
}

int
zynquartioctl(dev_t dev, u_long cmd, void *data, int flag, struct lwp *l)
{
        struct zynquart_softc *sc;
        struct tty *tp;
        int error;

        sc = device_lookup_private(&zynquart_cd, ZYNQUART_UNIT(dev));
        if (sc == NULL)
                return ENXIO;
        if (ZYNQUART_ISALIVE(sc) == 0)
                return (EIO);

        tp = sc->sc_tty;

        error = (*tp->t_linesw->l_ioctl)(tp, cmd, data, flag, l);
        if (error != EPASSTHROUGH)
                return (error);

        error = ttioctl(tp, cmd, data, flag, l);
        if (error != EPASSTHROUGH)
                return (error);

        error = 0;
        switch (cmd) {
        case TIOCSFLAGS:
                error = kauth_authorize_device_tty(l->l_cred,
                    KAUTH_DEVICE_TTY_PRIVSET, tp);
                break;
        default:
                /* nothing */
                break;
        }
        if (error) {
                return error;
        }

        mutex_spin_enter(&sc->sc_lock);

        switch (cmd) {
        case TIOCSBRK:
                zynquart_break(sc, true);
                break;

        case TIOCCBRK:
                zynquart_break(sc, false);
                break;

        case TIOCSDTR:
                zynquart_modem(sc, 1);
                break;

        case TIOCCDTR:
                zynquart_modem(sc, 0);
                break;

        case TIOCGFLAGS:
                *(int *)data = sc->sc_swflags;
                break;

        case TIOCSFLAGS:
                sc->sc_swflags = *(int *)data;
                break;

        case TIOCMSET:
        case TIOCMBIS:
        case TIOCMBIC:
                tiocm_to_zynquart(sc, cmd, *(int *)data);
                break;

        case TIOCMGET:
                *(int *)data = zynquart_to_tiocm(sc);
                break;

#ifdef notyet
        case PPS_IOC_CREATE:
        case PPS_IOC_DESTROY:
        case PPS_IOC_GETPARAMS:
        case PPS_IOC_SETPARAMS:
        case PPS_IOC_GETCAP:
        case PPS_IOC_FETCH:
#ifdef PPS_SYNC
        case PPS_IOC_KCBIND:
#endif
                mutex_spin_enter(&timecounter_lock);
                error = pps_ioctl(cmd, data, &sc->sc_pps_state);
                mutex_spin_exit(&timecounter_lock);
                break;

        case TIOCDCDTIMESTAMP:  /* XXX old, overloaded  API used by xntpd v3 */
                mutex_spin_enter(&timecounter_lock);
#ifndef PPS_TRAILING_EDGE
                TIMESPEC_TO_TIMEVAL((struct timeval *)data,
                    &sc->sc_pps_state.ppsinfo.assert_timestamp);
#else
                TIMESPEC_TO_TIMEVAL((struct timeval *)data,
                    &sc->sc_pps_state.ppsinfo.clear_timestamp);
#endif
                mutex_spin_exit(&timecounter_lock);
                break;
#endif

        default:
                error = EPASSTHROUGH;
                break;
        }

        mutex_spin_exit(&sc->sc_lock);

#ifdef ZYNQUART_DEBUG
        if (zynquart_debug)
                zynquartstatus(sc, "zynquartioctl ");
#endif

        return (error);
}

integrate void
zynquart_schedrx(struct zynquart_softc *sc)
{
        sc->sc_rx_ready = 1;

        /* Wake up the poller. */
        softint_schedule(sc->sc_si);
}

void
zynquart_break(struct zynquart_softc *sc, bool onoff)
{
        bus_space_tag_t iot = sc->sc_regs.ur_iot;
        bus_space_handle_t ioh = sc->sc_regs.ur_ioh;

        if (onoff)
                SET(sc->sc_cr, CR_STPBRK);
        else
                CLR(sc->sc_cr, CR_STPBRK);

        bus_space_write_4(iot, ioh, UART_CONTROL, sc->sc_cr);
}

void
zynquart_modem(struct zynquart_softc *sc, int onoff)
{
#ifdef notyet
        if (sc->sc_mcr_dtr == 0)
                return;

        if (onoff)
                SET(sc->sc_mcr, sc->sc_mcr_dtr);
        else
                CLR(sc->sc_mcr, sc->sc_mcr_dtr);

        if (!sc->sc_heldchange) {
                if (sc->sc_tx_busy) {
                        sc->sc_heldtbc = sc->sc_tbc;
                        sc->sc_tbc = 0;
                        sc->sc_heldchange = 1;
                } else
                        zynquart_loadchannelregs(sc);
        }
#endif
}

void
tiocm_to_zynquart(struct zynquart_softc *sc, u_long how, int ttybits)
{
        bus_space_tag_t iot = sc->sc_regs.ur_iot;
        bus_space_handle_t ioh = sc->sc_regs.ur_ioh;

        u_char combits;

        combits = 0;
        if (ISSET(ttybits, TIOCM_DTR))
                SET(combits, MODEMCR_DTR);
        if (ISSET(ttybits, TIOCM_RTS))
                SET(combits, MODEMCR_RTS);

        switch (how) {
        case TIOCMBIC:
                CLR(sc->sc_mcr, combits);
                break;

        case TIOCMBIS:
                SET(sc->sc_mcr, combits);
                break;

        case TIOCMSET:
                CLR(sc->sc_mcr, MODEMCR_DTR | MODEMCR_RTS);
                SET(sc->sc_mcr, combits);
                break;
        }

        bus_space_write_4(iot, ioh, UART_MODEM_CTRL, sc->sc_mcr);
}

int
zynquart_to_tiocm(struct zynquart_softc *sc)
{
#ifdef  notyet
        bus_space_tag_t iot = sc->sc_regs.ur_iot;
        bus_space_handle_t ioh = sc->sc_regs.ur_ioh;
#endif
        uint32_t combits;
        int ttybits = 0;

        combits = sc->sc_mcr;
        if (ISSET(combits, MODEMCR_DTR))
                SET(ttybits, TIOCM_DTR);
        if (ISSET(combits, MODEMCR_RTS))
                SET(ttybits, TIOCM_RTS);

        combits = sc->sc_msr;
        if (ISSET(combits, MODEMSR_DCD))
                SET(ttybits, TIOCM_CD);
        if (ISSET(combits, MODEMSR_CTS))
                SET(ttybits, TIOCM_CTS);
        if (ISSET(combits, MODEMSR_DSR))
                SET(ttybits, TIOCM_DSR);
        if (ISSET(combits, MODEMSR_RI | MODEMSR_TERI))
                SET(ttybits, TIOCM_RI);

#ifdef  notyet
        combits = bus_space_read_4(iot, ioh, UART_INTRPT_MASK);
        if (ISSET(sc->sc_imr, IER_ERXRDY | IER_ETXRDY | IER_ERLS | IER_EMSC))
                SET(ttybits, TIOCM_LE);
#endif

        return (ttybits);
}

static uint32_t
cflag_to_zynquart(tcflag_t cflag, uint32_t oldval)
{
        uint32_t val = oldval;

        CLR(val, MR_CHMODE | MR_NBSTOP | MR_PAR | MR_CHRL | MR_CLKS);

        switch (cflag & CSIZE) {
        case CS5:
                /* not suppreted. use 7-bits */
        case CS6:
                SET(val, CHRL_6BIT);
                break;
        case CS7:
                SET(val, CHRL_7BIT);
                break;
        case CS8:
                SET(val, CHRL_8BIT);
                break;
        }

        if (ISSET(cflag, PARENB)) {
                /* odd parity */
                if (!ISSET(cflag, PARODD))
                        SET(val, PAR_ODD);
                else
                        SET(val, PAR_EVEN);
        } else {
                SET(val, PAR_NONE);
        }

        if (ISSET(cflag, CSTOPB))
                SET(val, NBSTOP_2);

        return val;
}

int
zynquartparam(struct tty *tp, struct termios *t)
{
        struct zynquart_softc *sc =
            device_lookup_private(&zynquart_cd, ZYNQUART_UNIT(tp->t_dev));
        struct zynquart_baudrate_ratio ratio;
        uint32_t mcr;
        bool change_speed = tp->t_ospeed != t->c_ospeed;

        if (ZYNQUART_ISALIVE(sc) == 0)
                return (EIO);

        /* Check requested parameters. */
        if (t->c_ispeed && t->c_ispeed != t->c_ospeed)
                return (EINVAL);

        /*
         * For the console, always force CLOCAL and !HUPCL, so that the port
         * is always active.
         */
        if (ISSET(sc->sc_swflags, TIOCFLAG_SOFTCAR) ||
            ISSET(sc->sc_hwflags, ZYNQUART_HW_CONSOLE)) {
                SET(t->c_cflag, CLOCAL);
                CLR(t->c_cflag, HUPCL);
        }

        /*
         * If there were no changes, don't do anything.  This avoids dropping
         * input and improves performance when all we did was frob things like
         * VMIN and VTIME.
         */
        if ( !change_speed && tp->t_cflag == t->c_cflag)
                return (0);

        if (change_speed) {
                /* calculate baudrate modulator value */
                if (zynquartspeed(t->c_ospeed, &ratio) < 0)
                        return (EINVAL);
                sc->sc_ratio = ratio;
        }

        mcr = cflag_to_zynquart(t->c_cflag, sc->sc_mcr);

        mutex_spin_enter(&sc->sc_lock);

#if 0
        /* flow control stuff.  not yet */
        /*
         * If we're not in a mode that assumes a connection is present, then
         * ignore carrier changes.
         */
        if (ISSET(t->c_cflag, CLOCAL | MDMBUF))
                sc->sc_msr_dcd = 0;
        else
                sc->sc_msr_dcd = MSR_DCD;
        /*
         * Set the flow control pins depending on the current flow control
         * mode.
         */
        if (ISSET(t->c_cflag, CRTSCTS)) {
                sc->sc_mcr_dtr = MCR_DTR;
                sc->sc_mcr_rts = MCR_RTS;
                sc->sc_msr_cts = MSR_CTS;
                sc->sc_efr = EFR_AUTORTS | EFR_AUTOCTS;
        } else if (ISSET(t->c_cflag, MDMBUF)) {
                /*
                 * For DTR/DCD flow control, make sure we don't toggle DTR for
                 * carrier detection.
                 */
                sc->sc_mcr_dtr = 0;
                sc->sc_mcr_rts = MCR_DTR;
                sc->sc_msr_cts = MSR_DCD;
                sc->sc_efr = 0;
        } else {
                /*
                 * If no flow control, then always set RTS.  This will make
                 * the other side happy if it mistakenly thinks we're doing
                 * RTS/CTS flow control.
                 */
                sc->sc_mcr_dtr = MCR_DTR | MCR_RTS;
                sc->sc_mcr_rts = 0;
                sc->sc_msr_cts = 0;
                sc->sc_efr = 0;
                if (ISSET(sc->sc_mcr, MCR_DTR))
                        SET(sc->sc_mcr, MCR_RTS);
                else
                        CLR(sc->sc_mcr, MCR_RTS);
        }
        sc->sc_msr_mask = sc->sc_msr_cts | sc->sc_msr_dcd;
#endif

        /* And copy to tty. */
        tp->t_ispeed = t->c_ospeed;
        tp->t_ospeed = t->c_ospeed;
        tp->t_cflag = t->c_cflag;

        if (!change_speed && mcr == sc->sc_mcr) {
                /* noop */
        } else if (!sc->sc_pending && !sc->sc_tx_busy) {
                if (mcr != sc->sc_mcr) {
                        sc->sc_mcr = mcr;
                        zynquart_load_params(sc);
                }
                if (change_speed)
                        zynquart_load_speed(sc);
        } else {
                if (!sc->sc_pending) {
                        sc->sc_heldtbc = sc->sc_tbc;
                        sc->sc_tbc = 0;
                }
                sc->sc_pending |=
                    (mcr == sc->sc_mcr ? 0 : ZYNQUART_PEND_PARAM) |
                    (change_speed ? 0 : ZYNQUART_PEND_SPEED);
                sc->sc_mcr = mcr;
        }

        if (!ISSET(t->c_cflag, CHWFLOW)) {
                /* Disable the high water mark. */
                sc->sc_r_hiwat = 0;
                sc->sc_r_lowat = 0;
                if (ISSET(sc->sc_rx_flags, ZYNQUART_RX_TTY_OVERFLOWED)) {
                        CLR(sc->sc_rx_flags, ZYNQUART_RX_TTY_OVERFLOWED);
                        zynquart_schedrx(sc);
                }
                if (ISSET(sc->sc_rx_flags,
                        ZYNQUART_RX_TTY_BLOCKED|ZYNQUART_RX_IBUF_BLOCKED)) {
                        CLR(sc->sc_rx_flags,
                            ZYNQUART_RX_TTY_BLOCKED|ZYNQUART_RX_IBUF_BLOCKED);
                        zynquart_hwiflow(sc);
                }
        } else {
                sc->sc_r_hiwat = zynquart_rbuf_hiwat;
                sc->sc_r_lowat = zynquart_rbuf_lowat;
        }

        mutex_spin_exit(&sc->sc_lock);

        /*
         * Update the tty layer's idea of the carrier bit, in case we changed
         * CLOCAL or MDMBUF.  We don't hang up here; we only do that by
         * explicit request.
         */
        (void) (*tp->t_linesw->l_modem)(tp, ISSET(sc->sc_msr, MODEMSR_DCD));

#ifdef ZYNQUART_DEBUG
        if (zynquart_debug)
                zynquartstatus(sc, "zynquartparam ");
#endif

        if (!ISSET(t->c_cflag, CHWFLOW)) {
                if (sc->sc_tx_stopped) {
                        sc->sc_tx_stopped = 0;
                        zynquartstart(tp);
                }
        }

        return (0);
}

void
zynquart_iflush(struct zynquart_softc *sc)
{
        bus_space_tag_t iot = sc->sc_regs.ur_iot;
        bus_space_handle_t ioh = sc->sc_regs.ur_ioh;
#ifdef DIAGNOSTIC
        uint32_t reg = 0xffff;
#endif
        int timo;

        timo = 50000;
        /* flush any pending I/O */
        while (!ISSET(bus_space_read_4(iot, ioh, UART_CHANNEL_STS), STS_REMPTY) &&
            --timo)
#ifdef DIAGNOSTIC
                reg =
#else
                    (void)
#endif
                    bus_space_read_4(iot, ioh, UART_TX_RX_FIFO);

#ifdef DIAGNOSTIC
        if (!timo)
                aprint_error_dev(sc->sc_dev, "zynquart_iflush timeout %02x\n", reg);
#endif
}

int
zynquarthwiflow(struct tty *tp, int block)
{
        struct zynquart_softc *sc =
            device_lookup_private(&zynquart_cd, ZYNQUART_UNIT(tp->t_dev));

        if (ZYNQUART_ISALIVE(sc) == 0)
                return (0);

#ifdef notyet
        if (sc->sc_mcr_rts == 0)
                return (0);
#endif

        mutex_spin_enter(&sc->sc_lock);

        if (block) {
                if (!ISSET(sc->sc_rx_flags, ZYNQUART_RX_TTY_BLOCKED)) {
                        SET(sc->sc_rx_flags, ZYNQUART_RX_TTY_BLOCKED);
                        zynquart_hwiflow(sc);
                }
        } else {
                if (ISSET(sc->sc_rx_flags, ZYNQUART_RX_TTY_OVERFLOWED)) {
                        CLR(sc->sc_rx_flags, ZYNQUART_RX_TTY_OVERFLOWED);
                        zynquart_schedrx(sc);
                }
                if (ISSET(sc->sc_rx_flags, ZYNQUART_RX_TTY_BLOCKED)) {
                        CLR(sc->sc_rx_flags, ZYNQUART_RX_TTY_BLOCKED);
                        zynquart_hwiflow(sc);
                }
        }

        mutex_spin_exit(&sc->sc_lock);
        return (1);
}

/*
 * (un)block input via hw flowcontrol
 */
void
zynquart_hwiflow(struct zynquart_softc *sc)
{
#ifdef notyet
        struct zynquart_regs *regsp= &sc->sc_regs;

        if (sc->sc_mcr_rts == 0)
                return;

        if (ISSET(sc->sc_rx_flags, RX_ANY_BLOCK)) {
                CLR(sc->sc_mcr, sc->sc_mcr_rts);
                CLR(sc->sc_mcr_active, sc->sc_mcr_rts);
        } else {
                SET(sc->sc_mcr, sc->sc_mcr_rts);
                SET(sc->sc_mcr_active, sc->sc_mcr_rts);
        }
        UR_WRITE_1(regsp, ZYNQUART_REG_MCR, sc->sc_mcr_active);
#endif
}


void
zynquartstart(struct tty *tp)
{
        struct zynquart_softc *sc =
            device_lookup_private(&zynquart_cd, ZYNQUART_UNIT(tp->t_dev));
        int s;
        u_char *tba;
        int tbc;
        bus_space_tag_t iot = sc->sc_regs.ur_iot;
        bus_space_handle_t ioh = sc->sc_regs.ur_ioh;

        if (ZYNQUART_ISALIVE(sc) == 0)
                return;

        s = spltty();
        if (ISSET(tp->t_state, TS_BUSY | TS_TIMEOUT | TS_TTSTOP))
                goto out;
        if (sc->sc_tx_stopped)
                goto out;
        if (!ttypull(tp))
                goto out;

        /* Grab the first contiguous region of buffer space. */
        tba = tp->t_outq.c_cf;
        tbc = ndqb(&tp->t_outq, 0);

        mutex_spin_enter(&sc->sc_lock);

        sc->sc_tba = tba;
        sc->sc_tbc = tbc;

        SET(tp->t_state, TS_BUSY);
        sc->sc_tx_busy = 1;

        while (sc->sc_tbc > 0 &&
            !(bus_space_read_4(iot, ioh, UART_CHANNEL_STS) & STS_TFUL)) {
                bus_space_write_4(iot, ioh, UART_TX_RX_FIFO, *sc->sc_tba);
                sc->sc_tbc--;
                sc->sc_tba++;
        }

        /* Enable transmit completion interrupts */
        zynquart_control_txint(sc, true);

        mutex_spin_exit(&sc->sc_lock);
out:
        splx(s);
        return;
}

/*
 * Stop output on a line.
 */
void
zynquartstop(struct tty *tp, int flag)
{
        struct zynquart_softc *sc =
            device_lookup_private(&zynquart_cd, ZYNQUART_UNIT(tp->t_dev));

        mutex_spin_enter(&sc->sc_lock);
        if (ISSET(tp->t_state, TS_BUSY)) {
                /* Stop transmitting at the next chunk. */
                sc->sc_tbc = 0;
                sc->sc_heldtbc = 0;
                if (!ISSET(tp->t_state, TS_TTSTOP))
                        SET(tp->t_state, TS_FLUSH);
        }
        mutex_spin_exit(&sc->sc_lock);
}

void
zynquartdiag(void *arg)
{
#ifdef notyet
        struct zynquart_softc *sc = arg;
        int overflows, floods;

        mutex_spin_enter(&sc->sc_lock);
        overflows = sc->sc_overflows;
        sc->sc_overflows = 0;
        floods = sc->sc_floods;
        sc->sc_floods = 0;
        sc->sc_errors = 0;
        mutex_spin_exit(&sc->sc_lock);

        log(LOG_WARNING, "%s: %d silo overflow%s, %d ibuf flood%s\n",
            device_xname(sc->sc_dev),
            overflows, overflows == 1 ? "" : "s",
            floods, floods == 1 ? "" : "s");
#endif
}

integrate void
zynquart_rxsoft(struct zynquart_softc *sc, struct tty *tp)
{
        int (*rint)(int, struct tty *) = tp->t_linesw->l_rint;
        u_int cc, scc, outp;
        uint16_t data;
        u_int code;

        scc = cc = ZYNQUART_RBUF_AVAIL(sc);

#if 0
        if (cc == zynquart_rbuf_size-1) {
                sc->sc_floods++;
                if (sc->sc_errors++ == 0)
                        callout_reset(&sc->sc_diag_callout, 60 * hz,
                            zynquartdiag, sc);
        }
#endif

        /* If not yet open, drop the entire buffer content here */
        if (!ISSET(tp->t_state, TS_ISOPEN)) {
                sc->sc_rbuf_out = sc->sc_rbuf_in;
                cc = 0;
        }

        outp = sc->sc_rbuf_out;

#define ERRBITS (INT_PARE|INT_FRAME|INT_ROVR)

        while (cc) {
                data = sc->sc_rbuf[outp];
                code = data & 0xff;
                if (ISSET(__SHIFTOUT(data, ERROR_BITS), ERRBITS)) {
                        if (sc->sc_errors.err == 0)
                                callout_reset(&sc->sc_diag_callout,
                                    60 * hz, zynquartdiag, sc);
                        if (ISSET(__SHIFTOUT(data, ERROR_BITS), INT_ROVR))
                                sc->sc_errors.ovrrun++;
                        if (ISSET(__SHIFTOUT(data, ERROR_BITS), INT_FRAME)) {
                                sc->sc_errors.frmerr++;
                                SET(code, TTY_FE);
                        }
                        if (ISSET(__SHIFTOUT(data, ERROR_BITS), INT_PARE)) {
                                sc->sc_errors.prerr++;
                                SET(code, TTY_PE);
                        }
                }
                if ((*rint)(code, tp) == -1) {
                        /*
                         * The line discipline's buffer is out of space.
                         */
                        if (!ISSET(sc->sc_rx_flags, ZYNQUART_RX_TTY_BLOCKED)) {
                                /*
                                 * We're either not using flow control, or the
                                 * line discipline didn't tell us to block for
                                 * some reason.  Either way, we have no way to
                                 * know when there's more space available, so
                                 * just drop the rest of the data.
                                 */
                                sc->sc_rbuf_out = sc->sc_rbuf_in;
                                cc = 0;
                        } else {
                                /*
                                 * Don't schedule any more receive processing
                                 * until the line discipline tells us there's
                                 * space available (through zynquarthwiflow()).
                                 * Leave the rest of the data in the input
                                 * buffer.
                                 */
                                SET(sc->sc_rx_flags, ZYNQUART_RX_TTY_OVERFLOWED);
                        }
                        break;
                }
                outp = ZYNQUART_RBUF_INC(sc, outp, 1);
                cc--;
        }

        if (cc != scc) {
                sc->sc_rbuf_out = outp;
                mutex_spin_enter(&sc->sc_lock);

                cc = ZYNQUART_RBUF_SPACE(sc);

                /* Buffers should be ok again, release possible block. */
                if (cc >= sc->sc_r_lowat) {
                        if (ISSET(sc->sc_rx_flags, ZYNQUART_RX_IBUF_OVERFLOWED)) {
                                CLR(sc->sc_rx_flags, ZYNQUART_RX_IBUF_OVERFLOWED);
                                zynquart_control_rxint(sc, true);
                        }
                        if (ISSET(sc->sc_rx_flags, ZYNQUART_RX_IBUF_BLOCKED)) {
                                CLR(sc->sc_rx_flags, ZYNQUART_RX_IBUF_BLOCKED);
                                zynquart_hwiflow(sc);
                        }
                }
                mutex_spin_exit(&sc->sc_lock);
        }
}

integrate void
zynquart_txsoft(struct zynquart_softc *sc, struct tty *tp)
{

        CLR(tp->t_state, TS_BUSY);
        if (ISSET(tp->t_state, TS_FLUSH))
                CLR(tp->t_state, TS_FLUSH);
        else
                ndflush(&tp->t_outq, (int)(sc->sc_tba - tp->t_outq.c_cf));
        (*tp->t_linesw->l_start)(tp);
}

integrate void
zynquart_stsoft(struct zynquart_softc *sc, struct tty *tp)
{
#ifdef notyet
        u_char msr, delta;

        mutex_spin_enter(&sc->sc_lock);
        msr = sc->sc_msr;
        delta = sc->sc_msr_delta;
        sc->sc_msr_delta = 0;
        mutex_spin_exit(&sc->sc_lock);

        if (ISSET(delta, sc->sc_msr_dcd)) {
                /*
                 * Inform the tty layer that carrier detect changed.
                 */
                (void) (*tp->t_linesw->l_modem)(tp, ISSET(msr, MSR_DCD));
        }

        if (ISSET(delta, sc->sc_msr_cts)) {
                /* Block or unblock output according to flow control. */
                if (ISSET(msr, sc->sc_msr_cts)) {
                        sc->sc_tx_stopped = 0;
                        (*tp->t_linesw->l_start)(tp);
                } else {
                        sc->sc_tx_stopped = 1;
                }
        }

#endif
#ifdef ZYNQUART_DEBUG
        if (zynquart_debug)
                zynquartstatus(sc, "zynquart_stsoft");
#endif
}

void
zynquartsoft(void *arg)
{
        struct zynquart_softc *sc = arg;
        struct tty *tp;

        if (ZYNQUART_ISALIVE(sc) == 0)
                return;

        tp = sc->sc_tty;

        if (sc->sc_rx_ready) {
                sc->sc_rx_ready = 0;
                zynquart_rxsoft(sc, tp);
        }

        if (sc->sc_st_check) {
                sc->sc_st_check = 0;
                zynquart_stsoft(sc, tp);
        }

        if (sc->sc_tx_done) {
                sc->sc_tx_done = 0;
                zynquart_txsoft(sc, tp);
        }
}

int
zynquartintr(void *arg)
{
        struct zynquart_softc *sc = arg;
        uint32_t sts;
        uint32_t int_sts;
        bus_space_tag_t iot = sc->sc_regs.ur_iot;
        bus_space_handle_t ioh = sc->sc_regs.ur_ioh;

        if (ZYNQUART_ISALIVE(sc) == 0)
                return (0);

        mutex_spin_enter(&sc->sc_lock);

        int_sts = bus_space_read_4(iot, ioh, UART_CHNL_INT_STS);
        do {
                sts = bus_space_read_4(iot, ioh, UART_CHANNEL_STS);
                if (!(sts & STS_REMPTY))
                        zynquartintr_read(sc);
        } while (!(sts & STS_REMPTY));

        if (sts & STS_TEMPTY)
                zynquartintr_send(sc);

        bus_space_write_4(iot, ioh, UART_CHNL_INT_STS, int_sts);

        mutex_spin_exit(&sc->sc_lock);

        /* Wake up the poller. */
        softint_schedule(sc->sc_si);

#ifdef RND_COM
        rnd_add_uint32(&sc->rnd_source, iir | lsr);
#endif

        return (1);
}


/*
 * called when there is least one character in rxfifo
 *
 */

static void
zynquartintr_read(struct zynquart_softc *sc)
{
        int cc;
        uint16_t rd;
        uint32_t sts;
        bus_space_tag_t iot = sc->sc_regs.ur_iot;
        bus_space_handle_t ioh = sc->sc_regs.ur_ioh;

        cc = ZYNQUART_RBUF_SPACE(sc);

        /* clear aging timer interrupt */
        bus_space_write_4(iot, ioh, UART_CHNL_INT_STS, INT_TIMEOUT);

        while (cc > 0) {
                int cn_trapped = 0;

                sc->sc_rbuf[sc->sc_rbuf_in] = rd =
                    bus_space_read_4(iot, ioh, UART_TX_RX_FIFO);

                cn_check_magic(sc->sc_tty->t_dev,
                    rd & 0xff, zynquart_cnm_state);

                if (!cn_trapped) {
                        sc->sc_rbuf_in = ZYNQUART_RBUF_INC(sc, sc->sc_rbuf_in, 1);
                        cc--;
                }

                sts = bus_space_read_4(iot, ioh, UART_CHANNEL_STS);
                if (sts & STS_REMPTY)
                        break;
        }

        /*
         * Current string of incoming characters ended because
         * no more data was available or we ran out of space.
         * Schedule a receive event if any data was received.
         * If we're out of space, turn off receive interrupts.
         */
        if (!ISSET(sc->sc_rx_flags, ZYNQUART_RX_TTY_OVERFLOWED))
                sc->sc_rx_ready = 1;
        /*
         * See if we are in danger of overflowing a buffer. If
         * so, use hardware flow control to ease the pressure.
         */
        if (!ISSET(sc->sc_rx_flags, ZYNQUART_RX_IBUF_BLOCKED) &&
            cc < sc->sc_r_hiwat) {
                sc->sc_rx_flags |= ZYNQUART_RX_IBUF_BLOCKED;
                zynquart_hwiflow(sc);
        }

        /*
         * If we're out of space, disable receive interrupts
         * until the queue has drained a bit.
         */
        if (!cc) {
                sc->sc_rx_flags |= ZYNQUART_RX_IBUF_OVERFLOWED;
                zynquart_control_rxint(sc, false);
        }
}

void
zynquartintr_send(struct zynquart_softc *sc)
{
        uint32_t sts;
        bus_space_tag_t iot = sc->sc_regs.ur_iot;
        bus_space_handle_t ioh = sc->sc_regs.ur_ioh;

        sts = bus_space_read_4(iot, ioh, UART_CHANNEL_STS);

        if (sc->sc_pending) {
                if (sts & STS_TEMPTY) {
                        zynquart_load_pendings(sc);
                        sc->sc_tbc = sc->sc_heldtbc;
                        sc->sc_heldtbc = 0;
                } else {
                        /* wait for TX fifo empty */
                        zynquart_control_txint(sc, true);
                        return;
                }
        }

        while (sc->sc_tbc > 0 &&
            !(bus_space_read_4(iot, ioh, UART_CHANNEL_STS) & STS_TFUL)) {
                bus_space_write_4(iot, ioh, UART_TX_RX_FIFO, *sc->sc_tba);
                sc->sc_tbc--;
                sc->sc_tba++;
        }

        if (sc->sc_tbc > 0)
                zynquart_control_txint(sc, true);
        else {
                /* no more chars to send.
                   we don't need tx interrupt any more. */
                zynquart_control_txint(sc, false);
                if (sc->sc_tx_busy) {
                        sc->sc_tx_busy = 0;
                        sc->sc_tx_done = 1;
                }
        }
}

static void
zynquart_disable_all_interrupts(struct zynquart_softc *sc)
{
        bus_space_tag_t iot = sc->sc_regs.ur_iot;
        bus_space_handle_t ioh = sc->sc_regs.ur_ioh;

        bus_space_write_4(iot, ioh, UART_INTRPT_DIS, 0xffffffff);
}

static void
zynquart_control_rxint(struct zynquart_softc *sc, bool enable)
{
        bus_space_tag_t iot = sc->sc_regs.ur_iot;
        bus_space_handle_t ioh = sc->sc_regs.ur_ioh;
        uint32_t mask = INT_TIMEOUT | INT_PARE | INT_FRAME | INT_ROVR | INT_RFUL | INT_RTRIG;
        uint32_t sts;

        /* clear */
        sts = bus_space_read_4(iot, ioh, UART_CHNL_INT_STS);
        bus_space_write_4(iot, ioh, UART_CHNL_INT_STS, sts);

        if (enable)
                bus_space_write_4(iot, ioh, UART_INTRPT_EN, mask);
        else
                bus_space_write_4(iot, ioh, UART_INTRPT_DIS, mask);
}

static void
zynquart_control_txint(struct zynquart_softc *sc, bool enable)
{
        bus_space_tag_t iot = sc->sc_regs.ur_iot;
        bus_space_handle_t ioh = sc->sc_regs.ur_ioh;
        uint32_t mask = INT_TEMPTY;

        if (enable)
                bus_space_write_4(iot, ioh, UART_INTRPT_EN, mask);
        else
                bus_space_write_4(iot, ioh, UART_INTRPT_DIS, mask);
}


static void
zynquart_load_params(struct zynquart_softc *sc)
{
        bus_space_tag_t iot = sc->sc_regs.ur_iot;
        bus_space_handle_t ioh = sc->sc_regs.ur_ioh;

        bus_space_write_4(iot, ioh, UART_MODE, sc->sc_mcr);
}

static void
zynquart_load_speed(struct zynquart_softc *sc)
{
        /* bus_space_tag_t iot = sc->sc_regs.ur_iot; */
        /* bus_space_handle_t ioh = sc->sc_regs.ur_ioh; */

        /* XXX */
}


static void
zynquart_load_pendings(struct zynquart_softc *sc)
{
        if (sc->sc_pending & ZYNQUART_PEND_PARAM)
                zynquart_load_params(sc);
        if (sc->sc_pending & ZYNQUART_PEND_SPEED)
                zynquart_load_speed(sc);
        sc->sc_pending = 0;
}

/*
 * The following functions are polled getc and putc routines, shared
 * by the console and kgdb glue.
 *
 * The read-ahead code is so that you can detect pending in-band
 * cn_magic in polled mode while doing output rather than having to
 * wait until the kernel decides it needs input.
 */

#define READAHEAD_RING_LEN      16
static int zynquart_readahead[READAHEAD_RING_LEN];
static int zynquart_readahead_in = 0;
static int zynquart_readahead_out = 0;
#define READAHEAD_IS_EMPTY()    (zynquart_readahead_in==zynquart_readahead_out)
#define READAHEAD_IS_FULL()     \
        (((zynquart_readahead_in+1) & (READAHEAD_RING_LEN-1)) ==zynquart_readahead_out)

int
zynquart_common_getc(dev_t dev, struct zynquart_regs *regsp)
{
        int s = splserial();
        u_char c;
        bus_space_tag_t iot = regsp->ur_iot;
        bus_space_handle_t ioh = regsp->ur_ioh;
        uint32_t sts;

        /* got a character from reading things earlier */
        if (zynquart_readahead_in != zynquart_readahead_out) {

                c = zynquart_readahead[zynquart_readahead_out];
                zynquart_readahead_out = (zynquart_readahead_out + 1) &
                    (READAHEAD_RING_LEN-1);
                splx(s);
                return (c);
        }

        /* block until a character becomes available */
        while ((sts = bus_space_read_4(iot, ioh, UART_CHANNEL_STS))
            & STS_REMPTY)
                continue;

        c = 0xff & bus_space_read_4(iot, ioh, UART_TX_RX_FIFO);

        if (!db_active) {
                int cn_trapped __unused = 0;
                cn_check_magic(dev, c, zynquart_cnm_state);
        }
        splx(s);
        return (c);
}

void
zynquart_common_putc(dev_t dev, struct zynquart_regs *regsp, int c)
{
        int s = splserial();
        int cin, timo;
        bus_space_tag_t iot = regsp->ur_iot;
        bus_space_handle_t ioh = regsp->ur_ioh;

        if (!READAHEAD_IS_FULL() &&
            !(bus_space_read_4(iot, ioh, UART_CHANNEL_STS) & STS_REMPTY)) {
                int cn_trapped __unused = 0;

                cin = bus_space_read_4(iot, ioh, UART_TX_RX_FIFO);
                cn_check_magic(dev, cin & 0xff, zynquart_cnm_state);
                zynquart_readahead_in = (zynquart_readahead_in + 1) &
                    (READAHEAD_RING_LEN-1);
        }

        /* wait for any pending transmission to finish */
        timo = 150000;
        do {
                if (!(bus_space_read_4(iot, ioh, UART_CHANNEL_STS) & STS_TFUL)) {
                        bus_space_write_4(iot, ioh, UART_TX_RX_FIFO, c);
                        break;
                }
        } while(--timo > 0);

        ZYNQUART_BARRIER(regsp, BR | BW);

        splx(s);
}

/*
 * Initialize UART for use as console or KGDB line.
 */
int
zynquart_init(struct zynquart_regs *regsp, int rate, tcflag_t cflag)
{
        struct zynquart_baudrate_ratio ratio;

        if (bus_space_map(regsp->ur_iot, regsp->ur_iobase, UART_SIZE, 0,
                &regsp->ur_ioh))
                return ENOMEM; /* ??? */

        if (zynquartspeed(rate, &ratio) < 0)
                return EINVAL;

        /* clear status registers */
        bus_space_write_4(regsp->ur_iot, regsp->ur_ioh, UART_CHNL_INT_STS, 0xffff);
        bus_space_write_4(regsp->ur_iot, regsp->ur_ioh, UART_CHANNEL_STS, 0xffff);

        return (0);
}



/*
 * Following are all routines needed for UART to act as console
 */
struct consdev zynquartcons = {
        .cn_getc = zynquartcngetc,
        .cn_putc = zynquartcnputc,
        .cn_pollc = nullcnpollc,
        .cn_dev = NODEV,
        .cn_pri = CN_NORMAL,
};


int
zynquart_cons_attach(bus_space_tag_t iot, paddr_t iobase, u_int rate,
                    tcflag_t cflag)
{
        struct zynquart_regs regs;
        int res;

        regs.ur_iot = iot;
        regs.ur_iobase = iobase;

        res = zynquart_init(&regs, rate, cflag);
        if (res)
                return (res);

        cn_tab = &zynquartcons;
        cn_init_magic(&zynquart_cnm_state);
        cn_set_magic("\047\001"); /* default magic is BREAK */

        zynquartconsrate = rate;
        zynquartconscflag = cflag;

        zynquartconsregs = regs;

        return 0;
}

int
zynquartcngetc(dev_t dev)
{
        return (zynquart_common_getc(dev, &zynquartconsregs));
}

/*
 * Console kernel output character routine.
 */
void
zynquartcnputc(dev_t dev, int c)
{
        zynquart_common_putc(dev, &zynquartconsregs, c);
}

#ifdef KGDB
int
zynquart_kgdb_attach(bus_space_tag_t iot, paddr_t iobase, u_int rate,
    tcflag_t cflag)
{
        int res;

        if (iot == zynquartconsregs.ur_iot &&
            iobase == zynquartconsregs.ur_iobase) {
#if !defined(DDB)
                return (EBUSY); /* cannot share with console */
#else
                zynquart_kgdb_regs.ur_iot = iot;
                zynquart_kgdb_regs.ur_ioh = zynquartconsregs.ur_ioh;
                zynquart_kgdb_regs.ur_iobase = iobase;
#endif
        } else {
                zynquart_kgdb_regs.ur_iot = iot;
                zynquart_kgdb_regs.ur_iobase = iobase;

                res = zynquart_init(&zynquart_kgdb_regs, rate, cflag);
                if (res)
                        return (res);

                /*
                 * XXXfvdl this shouldn't be needed, but the cn_magic goo
                 * expects this to be initialized
                 */
                cn_init_magic(&zynquart_cnm_state);
                cn_set_magic("\047\001");
        }

        kgdb_attach(zynquart_kgdb_getc, zynquart_kgdb_putc, &zynquart_kgdb_regs);
        kgdb_dev = 123; /* unneeded, only to satisfy some tests */

        return (0);
}

/* ARGSUSED */
int
zynquart_kgdb_getc(void *arg)
{
        struct zynquart_regs *regs = arg;

        return (zynquart_common_getc(NODEV, regs));
}

/* ARGSUSED */
void
zynquart_kgdb_putc(void *arg, int c)
{
        struct zynquart_regs *regs = arg;

        zynquart_common_putc(NODEV, regs, c);
}
#endif /* KGDB */

/* helper function to identify the zynquart ports used by
 console or KGDB (and not yet autoconf attached) */
int
zynquart_is_console(bus_space_tag_t iot, bus_addr_t iobase, bus_space_handle_t *ioh)
{
        bus_space_handle_t help;

        if (!zynquartconsattached &&
            iot == zynquartconsregs.ur_iot && iobase == zynquartconsregs.ur_iobase)
                help = zynquartconsregs.ur_ioh;
#ifdef KGDB
        else if (!zynquart_kgdb_attached &&
            iot == zynquart_kgdb_regs.ur_iot && iobase == zynquart_kgdb_regs.ur_iobase)
                help = zynquart_kgdb_regs.ur_ioh;
#endif
        else
                return (0);

        if (ioh)
                *ioh = help;
        return (1);
}

#ifdef notyet

bool
zynquart_cleanup(device_t self, int how)
{
/*
 * this routine exists to serve as a shutdown hook for systems that
 * have firmware which doesn't interact properly with a zynquart device in
 * FIFO mode.
 */
        struct zynquart_softc *sc = device_private(self);

        if (ISSET(sc->sc_hwflags, ZYNQUART_HW_FIFO))
                UR_WRITE_1(&sc->sc_regs, ZYNQUART_REG_FIFO, 0);

        return true;
}
#endif

#ifdef notyet
bool
zynquart_suspend(device_t self PMF_FN_ARGS)
{
        struct zynquart_softc *sc = device_private(self);

        UR_WRITE_1(&sc->sc_regs, ZYNQUART_REG_IER, 0);
        (void)CSR_READ_1(&sc->sc_regs, ZYNQUART_REG_IIR);

        return true;
}
#endif

#ifdef notyet
bool
zynquart_resume(device_t self PMF_FN_ARGS)
{
        struct zynquart_softc *sc = device_private(self);

        mutex_spin_enter(&sc->sc_lock);
        zynquart_loadchannelregs(sc);
        mutex_spin_exit(&sc->sc_lock);

        return true;
}
#endif

static void
zynquart_enable_debugport(struct zynquart_softc *sc)
{
        /* bus_space_tag_t iot = sc->sc_regs.ur_iot; */
        /* bus_space_handle_t ioh = sc->sc_regs.ur_ioh; */
}


void
zynquart_set_frequency(u_int freq, u_int div)
{
        zynquart_freq = freq;
        zynquart_freqdiv = div;
}